Optical and X - ray characteristics of a newly discovered narrow - line QSO : RX J 1334 . 2 + 3759

We report the discovery of a narrow-line QSO (NLQSO) RX J1334.2+3759 with a steep soft X-ray spectrum. Soft X-ray emission from the NLQSO is highly variable. Changes in the intensity by a factor of ∼ 2 have been detected in the ROSAT PSPC observations of RX J1334.2+3759 on time scales of∼ 20000−40000 s. Rapid variability events have also been observed from RX J1334.2+3759. The most extreme variable event has ∆L ∆t = (1.95±1.02)×10 erg s corresponding to a change in intensity by a factor of ∼ 4 within <∼ 400 s. The PSPC spectra of the NLQSO can be well represented by a power-law of photon index, ΓX ∼ 3.8 modified by an absorbing column local to the source (∆NH ∼ 3.3×10 20 cm) over and above that due to our own Galaxy (NH = 7.9×10 cm). The intrinsic soft X-ray luminosity of RX J1334.2+3759 is estimated to be ∼ 2.2×10 erg s in the energy band of 0.1−2.0 keV. The optical spectrum of RX J1334.2+3759 is typical of the NLS1 galaxies showing strong Balmer Hβ, Hα, and forbidden line of [O III]λ5007. Fe II multiplets, usually present in the optical spectra of NLS1 galaxies, are also detected from RX J1334.2+3759. Decomposition of the Hβ and Hα line profiles shows the presence of narrow (FWHM ∼ 880 km s) and broad (FWHM ∼ 2850 km s) components in the spectrum of RX J1334.2+3759. The narrow-line region of RX J1334.2+3759 appears to be significantly different from those of normal Seyfert galaxies. A possible explanation for the observed properties of the narrow line region and the broad line region is suggested in terms of density enhancements.